JP5666349B2 - Image forming apparatus, image forming method, program, and recording medium - Google Patents

Description

  The present invention relates to an image processing apparatus, an image forming apparatus, an image processing method, a program, and a recording medium that create a combined image by combining a composition image with a document image.

  2. Description of the Related Art In recent years, the copying accuracy of image forming apparatuses that perform copying has improved, so that original images such as documents can be easily copied and reproduced with high accuracy. In such a high-performance image forming apparatus, for example, illegal copying such as copying a specific document image that should be prohibited from copying to create an illegal copy is easily performed. Therefore, in order to prevent illegal copying of a specific document image, a technique for synthesizing a copy protection pattern, a watermark character, or the like with a specific document image has been realized.

  For example, in Patent Document 1, the background portion of the input image and the warning character portion to be combined with the background portion have a common density, and different dither processing is applied to the background portion and the warning character portion. A technique for creating a combined image by combining two images is disclosed.

  In this technique, in the original document image, the warning character portion and the background portion are dots having a constant area ratio. For this reason, the warning character portion and the background portion look almost uniform in density with the difference in the number of lines of halftone dots being inconspicuous with the naked eye. That is, the warning character part is hidden behind the background part and appears as a gray image area as a whole. On the other hand, when the synthesized image is copied, the number of lines of halftone dots is different between the warning character portion and the background portion, so that an image having a moire difference (warning character portion) appears on the recording paper. Therefore, the synthesized image has the same function as the copy forgery prevention paper.

  Patent Document 2 discloses a technique for printing a latent image, which cannot be identified with the naked eye under normal visible light, and appears on irradiation with ultraviolet rays, on a basic image. In this technology, a basic image having a uniform density is formed on a substrate, and this basic image cannot be distinguished with the naked eye under visible light, but appears with colored fluorescent ink so that it appears when irradiated with ultraviolet light. The image is printed.

  Patent Document 3 discloses a technique for forming a latent image on a substrate that cannot be identified with the naked eye under normal visible light and can be confirmed with an infrared display device. In this technique, a background pattern as a latent image is printed on a substrate with infrared absorbing ink, and the presence or absence of the background pattern is observed with an infrared display device.

Japanese Patent Laid-Open No. 7-231384 (released on August 29, 1995) WO-2001 / 094122 specification (December 13, 2001) JP 2008-105241 A (May 8, 2008)

  In the technique of Patent Document 1, since the warning character part is embedded as a composite image in the composited image, an effect of suppressing copying from the composited image can be obtained. In addition, when copying a composited image, it is possible to easily detect an embedded composite image visually. On the other hand, in the copy of the synthesized image, there is a problem that as a result of the appearance of the image for synthesis, the image for synthesis is easily visually recognized and the copied image is difficult to see. .

  On the other hand, with the techniques of Patent Documents 2 and 3, there is hardly a problem that a latent image appears under visible light and it becomes difficult to see a copied image. However, the formation of a latent image requires printing with special ink. Furthermore, in order to confirm the latent image, there is a problem that a special light source that irradiates light of a specific wavelength such as ultraviolet rays or infrared rays is required.

  The present invention has been made in order to solve the above-described problems, and in the first synthesized image print image obtained by synthesizing the image for synthesis with the document image, it is difficult to see the document image by the image for synthesis. In order to make it possible to visually recognize the composition image in the print image of the second composite image created by reading the print image of the first composite image that can be prevented, special inks such as ultraviolet light sources and infrared light sources are used. An object of the present invention is to provide an image processing apparatus, an image forming apparatus, an image processing method, a program, and a recording medium that do not require a light source.

  In order to solve the above-described problems, an image processing apparatus according to the present invention includes a first composition processing unit that composes a composition image in a composition image composition area of a document image to create a first composite image. In the image processing apparatus, the first synthesis processing unit is configured to measure each pixel of the synthesis image under a first light source on the color measurement of the first print image obtained by printing the first synthesized image. Under the second light source, the pixel value of each pixel of the composition image is the same color under the condition that the value is equal to the pixel value of each corresponding pixel in the composition image composition region, and the spectral characteristics are different from the first light source. The composition image is set so as to have a pixel value different from the pixel value of each corresponding pixel in the composition image composition area, and the composition image is composed in the composition image composition area of the document image and the first composition completed. It is characterized by creating images.

  The image processing method of the present invention is an image processing method comprising a first compositing process step of creating a first composited image by compositing a compositing image in a compositing image compositing area of a document image. In one compositing process step, on the colorimetry of the first print image obtained by printing the first composite image, the pixel value of each pixel of the composite image is the composite image composite under the first light source. The pixel value of each pixel of the image for synthesis corresponds to the image synthesis area for synthesis under a second light source that has the same color condition as the pixel value of each pixel corresponding to the area and has a spectral characteristic different from that of the first light source. The first synthesized image is created by synthesizing the synthesis image with the synthesis image synthesis area of the document image by setting the pixel value to be different from the pixel value of each pixel. It is said.

  According to the above configuration, the first synthesis processing unit (in the first synthesis processing step) performs synthesis under the first light source on the colorimetric measurement of the first print image obtained by printing the first synthesized image. The pixel value of each pixel of the image for use is the same color under the condition that the pixel value of the corresponding pixel of the image composition region for synthesis is the same, and the spectral characteristics of the pixels of the image for synthesis are different under the second light source. The first synthesized image is synthesized by setting the pixel value to be different from the pixel value of each corresponding pixel in the compositing image composition area, and compositing the compositing image with the compositing image composition area of the original image. Create

  Therefore, in the printed image obtained by scanning the first synthesized image obtained by synthesizing the synthesis image with the original image using the first light source, it is possible to prevent the original image from being difficult to see due to the synthesis image.

  Further, the first read image obtained by reading the print image of the first combined image with the first light source, and the second read image obtained by reading the print image of the first combined image with the second light source. The image for synthesis can be easily extracted. Therefore, special ink and special light sources such as an ultraviolet light source and an infrared light source are used in order to make the composition image visible in the print image of the second composite image created by reading the print image of the first composite image. I don't need it.

  An image forming apparatus according to the present invention includes the above-described image processing apparatus and a document reading device that reads a document image. The document reading device includes the first light source and the second light source, and the document image is converted into the document image. Reading with a first light source and a second light source, obtaining a first read image with the first light source and a second read image with the second light source, and the image processing device for the first print image. It is good also as a structure provided with the discrimination | determination part which compares a read image with the said 2nd read image, and discriminate | determines the presence or absence of the said image for a synthesis | combination in a said 1st print image.

  According to the above configuration, the document reading device reads the document image with the first light source and the second light source, and acquires the first read image with the first light source and the second read image with the second light source. The determination unit of the image processing apparatus includes a first read image (for example, each pixel value of the first read image) and a second read image (for example, each pixel value of the first read image) for the first print image. Each pixel value of the image) is compared to determine the presence or absence of a composition image in the first print image.

  Therefore, the determination unit of the image processing apparatus can easily determine the presence / absence of the composition image in the first print image from the first read image and the second read image of the first print image.

  In the above image forming apparatus, the image processing apparatus includes a second synthesis processing unit, and when the determination unit determines that the synthesis image is present in the first print image, the image processing apparatus The original image is extracted, and the second synthesis processing unit determines the first pixel for the synthesis image when the discrimination unit determines that the synthesis image is present in the first print image. 2 adopts the pixel value of the read image, and employs the original image pixel extracted by the discriminating unit for the other pixels, and synthesizes the original image and the image for composition, and the second composition It may be configured to create a completed image.

  According to the above configuration, the determination unit extracts the composition image and the document image when determining that the composition image is present in the first print image. The second compositing processing unit adopts the pixel value of the second read image for the pixel of the compositing image when the discriminating unit determines that the compositing image is present in the first print image. For the pixels, the pixels of the original image extracted by the determination unit are employed, and the original image and the image for synthesis are combined to create a second combined image.

  Thereby, the 2nd synthesized image which made the image for composition visible can be created appropriately.

  The image forming apparatus includes the image processing apparatus and a printing apparatus that prints an image on paper. The printing apparatus is a combination of toner including a color material having an absorption component and a reflection component in a visible light range. The first combined image may be printed.

  According to said structure, a printing apparatus prints a 1st synthesized image with the combination of the toner containing the color material which has an absorption component and a reflection component in a visible light region. Therefore, it is possible to easily print the first combined image by using a conventionally used toner as a developer.

  According to the configuration of the present invention, in the printed image obtained by scanning the first combined image obtained by combining the original image with the original image with the first light source and printing, it is possible to prevent the original image from being difficult to see due to the combining image. be able to. In addition, special ink and special light sources such as an ultraviolet light source and an infrared light source are provided in order to make the composition image visible in the print image of the second composite image created by reading the print image of the first composite image. Is not required.

1 is a block diagram illustrating a configuration of an image forming apparatus according to an embodiment of the present invention. 2A is a graph showing the spectral characteristics of cyan toner used in the color image output apparatus shown in FIG. 1, FIG. 2B is a graph showing the spectral characteristics of the magenta toner, and FIG. 2C. Is a graph showing the spectral characteristics of the yellow toner, and FIG. 2D is a graph showing the spectral characteristics of the black toner. FIG. 3A is a graph showing spectral characteristics in a first example of a combination of toner sets having the same color that is used in the color image output apparatus shown in FIG. 1, and FIG. FIG. 3C is a graph showing spectral characteristics in the second example of the combination of toner groups having the same color as the above condition, and FIG. 3D is a diagram illustrating the content of the combination of toner groups in the example. FIG. 3E is a graph showing the spectral characteristics in the third example of the combination of toner groups having the same color condition, and FIG. FIG. 7 is an explanatory diagram illustrating the content of a combination of toner groups in an example. It is a longitudinal cross-sectional view which shows the structure of the color image input device shown in FIG. FIG. 2 is an explanatory diagram illustrating a basic screen of an operation panel included in the image forming apparatus illustrated in FIG. 1. 3 is a flowchart showing a composition process in a color correction / black generation unit of the color image processing apparatus shown in FIG. 1. 3 is a flowchart illustrating an operation in the case of reading a first combined image printed on a sheet in the image forming apparatus illustrated in FIG. 1. 3 is a graph showing spectral characteristics of a first light source and a second light source of the color image input apparatus shown in FIG. 1. FIG. 9A is a graph showing spectral characteristics in the first example of the combination of print colors of the same color, and FIG. 9B is a measurement of the color under the first light source and the second light source for the first example. FIG. 9C is a graph showing spectral characteristics in the second example of combinations of print colors of the same color, and FIG. 9D is a diagram showing the second light source and the second light source in the second example. FIG. 9E is a graph showing spectral characteristics in the third example of combinations of print colors of the same condition, and FIG. 9F is a first example of the third example. It is explanatory drawing which shows the measured value of the color under a light source and a 2nd light source. FIG. 10A is an explanatory diagram showing an example of a document image used in the embodiment of the present invention, and FIG. 10B is an explanatory diagram showing an example of a composition image combined with the document image. It is explanatory drawing which shows an example of the 1st synthesized image created in the process of S14 of FIG. 12A is an explanatory diagram showing the first read image acquired in the process of S32 in FIG. 7, and FIG. 12B is an explanatory diagram showing the second read image acquired in the process of S34 in FIG. is there. FIG. 13A is an explanatory diagram showing a difference between the first read image and the second read image determined in the process of S35 of FIG. 7, and FIG. 13B is a diagram created in the process of S36 of FIG. It is explanatory drawing which shows 2 synthesized images.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a block diagram illustrating a configuration of the image forming apparatus 100. As shown in FIG. 1, an image forming apparatus 100 according to an embodiment of the present invention includes a color image input device 200, a color image processing device 300, and a color image output device 400.

  The color image input device 200 inputs a document image signal to the color image processing device 300. When the color image input device 200 is composed of a scanner, for example, the color image input device 200 scans a document image with a light source, reads a reflected light image from the document image with a CCD (Charge Coupled Device), and performs RGB (R: red). , G: green, B: blue) A document image signal composed of an analog signal is acquired. When the color image input device 200 is composed of, for example, a PC (personal computer), the color image input device 200 transmits an RGB image signal as a document image signal to the color image processing device 300 via a printer driver.

  The color image output apparatus 400 is an apparatus that outputs a document image signal that has been subjected to predetermined image processing by the color image processing apparatus 300, and is, for example, a printer.

  A color image processing apparatus 300 includes an A / D (analog / digital) conversion unit 10, a shading correction unit 11, a document type automatic discrimination unit 12, an input tone correction unit 13, a region separation processing unit 14, a color correction / black generation unit. (First synthesis processing unit, second synthesis processing unit, determination unit) 15, spatial filter processing unit 16, output tone correction unit 17, tone reproduction processing unit 18, and storage unit 19.

  The A / D converter 10 converts an analog document image signal input from the color image input device 200 into a digital document image signal.

  The shading correction unit 11 removes various distortions generated in the illumination system, imaging system, and imaging system of the color image input device 200 from the RGB document image signal input from the A / D conversion unit 10. I do.

  The document type automatic discrimination unit 12 uses an RGB signal (RGB reflectance signal) as a document image signal from which various distortions have been removed by the shading correction unit 11 in the color image processing apparatus 300. It is converted into a density signal that is easy to handle. Thereafter, the document type for the document image signal is determined. In the determination of the document type, it is determined whether the document image indicated by the document image signal is, for example, a character document, a photographic document, or a character / photo document combining them.

  The input tone correction unit 13 adjusts the color balance of the document image signal. At the same time, based on the determination result of the document type automatic determination unit 12, image quality adjustment processing for adjusting the background density, contrast, and the like is performed on the document image signal.

  The region separation processing unit 14 separates the document image indicated by the document image signal into a character, halftone dot, or photographic region for each pixel based on the determination result of the document type automatic determination unit 12. Further, a composition image to be synthesized with the document image is also separated as a composition image area. Further, the area separation processing unit 14 generates an area identification signal indicating which area each pixel belongs to based on the result of separating each pixel of the document image signal, and outputs a color correction unit / black generation unit 15 and a spatial filter process. To the unit 16 and the gradation reproduction processing unit 18.

  The color correction / black generation unit 15 converts the RGB signal values in the original image signal into spectral characteristics of CMYK (C: cyan, M: magenta, Y: yellow, K: black) color materials for faithful color reproduction. Is converted into a four-color signal based on the above. After that, the color correction / black generation unit 15 refers to the composition image stored in the storage unit 19 when the instruction to synthesize the composition image with the document image is input, and performs the composition for the document image. The image is combined to create a combined image.

  The composition image holds the position information of the composition image composition area in the original image, that is, the composition image composition area. Therefore, in the above-described synthesis process, the color correction / black generation unit 15 refers to the synthesis image, and for the color in the synthesis image synthesis region, conditions for normal color correction in the color correction / black generation unit 15, etc. By performing color correction to be a color, a composited image is created in the composite image composition region. The color correction that is the same color as the above condition is the same color under the first light source (first light source 55), but under the second light source (second light source 56) having a spectral wavelength characteristic different from that of the first light source. Color correction that results in different colors. In the color correction to be the condition equal color, the color of the image synthesis area for synthesis is designated with reference to the color correction lookup table showing the combination of colors to be the condition equal color.

  The spatial filter processing unit 16 performs spatial filter processing using a digital filter on the document image signal processed by the color correction / black generation unit 15 to correct the spatial frequency characteristics. Thereby, sharpness enhancement and moire improvement of the output image are performed.

  The output tone correction unit 17 performs output tone correction processing for converting a signal such as a density signal into a halftone dot area ratio that is a characteristic value of the color image output device 400.

  As the halftone generation process, the gradation reproduction processing unit 18 finally divides the document image signal for each pixel so as to reproduce the gradation of each pixel.

  For the image area extracted as a black character or a color character by the area separation processing unit 14, the spatial filter processing unit 16 uses a high-frequency sharpness enhancement process to improve the reproducibility of the black character or the color character area. Increase the amount of emphasis. At the same time, in the halftone generation process in the gradation reproduction processing unit 18, a binarization process or a multi-value process on a high resolution screen suitable for high frequency reproduction is selected.

  On the other hand, for the region extracted as a halftone dot by the region separation processing unit 14, the spatial filter processing unit 16 performs low-pass filter processing for removing the input halftone component. At the same time, in the halftone generation process in the gradation reproduction processing unit 18, binarization or multilevel conversion is performed on the screen with an emphasis on gradation reproducibility.

  The image data subjected to each processing as described above is stored in the storage unit 500, read out from the storage unit 500 at a predetermined timing, and input to the color image output apparatus 400.

  The color image output apparatus 400 is a printer that prints image data on a recording sheet, and is, for example, an electrophotographic system or an inkjet system. In addition, the process in each part is controlled by the control part 600 which consists of CPU (Central Processing Unit).

  The color reproduction in the color image processing apparatus 300 according to the present embodiment is performed by, for example, CMYK using the RGB luminance signal obtained by the document reading operation in the color image input apparatus 200 as a scanner in the color image output apparatus 400. The signal is color-converted. In this case, color conversion to a different signal format uses a color correction table in which a first conversion lookup table (hereinafter referred to simply as “LUT”) and a second conversion LUT are combined. . The first conversion LUT converts the RGB luminance signal into the common color space CIELAB, and is provided in the color image processing apparatus 300 in advance. The second conversion LUT converts the common color space CIELAB to the CMYK values of the toner of the color image output device 400.

  The second conversion LUT prints a toner patch with a changed CMYK ratio (halftone dot area ratio) in the color image output apparatus 400, measures it, acquires spectral characteristic information, and obtains a color value (CIELAB). Create by converting to. In this case, the measurement of the toner patch and the conversion to the color value are performed using a standard light source such as D50, assuming the observation of the printed matter under natural light. On the other hand, there may be a plurality of CMYK ratios showing the same color value under a specific light source. This is because of the condition color matching phenomenon that shows the same LAB when converted to the standard color space under a specific light source even when the spectral characteristics of the colors expressed by overlapping the CMYK halftone dots of the color material are different.

  Next, toner used in the color image output apparatus 400 will be described. 2A is a graph showing spectral characteristics of cyan toner, FIG. 2B is a graph showing spectral characteristics of magenta toner, FIG. 2C is a graph showing spectral characteristics of yellow toner, and FIG. 2D. Is a graph showing the spectral characteristics of black toner.

  The CMYK toner used in the color image output apparatus 400 is manufactured by a general method. As the coloring material, an organic pigment having absorption characteristics and reflection characteristics in the visible light region is used. Specifically, the cyan pigment is copper phthalocyanine, the magenta pigment is dimethylquinacridone, the yellow pigment is benzimidazolone, and the black pigment is carbon black.

  When each image of CMYK toner is printed on plain paper by the color image output device 400, the spectral characteristics of the color toner images are as shown in the graphs of FIGS. 2 (a) to 2 (d). In each graph, the horizontal axis indicates the wavelength (nm), and the vertical axis indicates the spectral reflectance. The spectral reflectance is measured under the condition of the standard light source D50 and the viewing angle of 2 °, and the L * a * b * value is calculated from the spectral reflectance according to the definition of CIELAB.

  Here, as described above, when an image is printed with toner of two or more colors, even if the spectral characteristics are different, the same color is recognized as the same color under the D50 standard light source or daylight There are a plurality of combinations of toner groups. FIG. 3A is a graph showing the spectral characteristics in the first example of the combination of toner sets having the same color, and FIG. 3B is an explanatory diagram showing the contents of the combination of toner sets in the first example. FIG. 3C is a graph showing the spectral characteristics in the second example of the combination of toner sets having the same color, and FIG. 3D is an explanatory diagram showing the contents of the combination of toner sets in the second example. FIG. 3E is a graph showing the spectral characteristics in the third example of the combination of toner sets having the same color, and FIG. 3F is an explanatory diagram showing the contents of the combination of toner sets in the third example. Note that the combination of each color toner set is not limited to these. In particular, a color containing K toner as a color component can often be replaced by mixing the K toner component with C, M, and Y toners, and there are many combinations of colors having the same color as conditions.

Specifically, for each combination example, in FIG.
The toner set p1 has C = 0%, M = 0%, Y = 0%, K = 100%,
The toner set p2 is C = 90%, M = 80%, Y = 80%, K = 35%,
The colors L * a * b * under the standard light source when printed with the toner sets p1 and p2 are different from each other as shown in FIG. 3B, and the spectral characteristics are as shown in FIG. 3A.

Similarly, in FIG.
The toner set q1 has C = 0%, M = 0%, Y = 0%, K = 50%,
The toner set q2 is C = 40%, M = 25%, Y = 30%, K = 0%,
The colors L * a * b * under the standard light source when printed with toner sets q1 and q2 are different from each other as shown in FIG. 3D, and the spectral characteristics are as shown in FIG. 3C.

Similarly, in FIG.
The toner set r1 has C = 50%, M = 0%, Y = 0%, K = 50%,
The toner set r2 has C = 70%, M = 30%, Y = 30%, K = 0%,
When the toner sets r1 and r2 are printed, the colors L * a * b * under a standard light source are different from each other as shown in FIG. 3 (f), and the spectral characteristics are as shown in FIG. 3 (e).

  When using a combination of these toner groups, the color image output device 400 prints in advance with these toner groups, measures the printed image to obtain spectral characteristics, and stores them as, for example, a lookup table in the storage unit 19. Just keep it.

  Next, the configuration of the color image input apparatus 200 as a scanner will be described. FIG. 4 is a longitudinal sectional view showing the configuration of the color image input apparatus 200 shown in FIG.

  As shown in FIG. 4, the color image input apparatus 200 includes a glass platen 50, an optical drive unit 51, a scanner lamp unit 52, an image reading unit 53, a signal processing unit 54, a first mirror 60, a second mirror 61, and A third mirror 62 is provided.

  The scanner lamp unit 52 includes a first light source 55 and a second light source 56 that are scanner lamps. The first light source 55 and the second light source 56 are arranged so that the irradiation angles to the document 57 are different from each other.

  The first light source 55 and the second light source 56 are lamps having different spectral wavelength characteristics, and for example, a fluorescent tube or a white LED is used. Specifically, the first light source 55 is a light source that cannot recognize an image for synthesis of the same color that is combined with the original image, and is, for example, a xenon lamp. The second light source is a light source capable of recognizing a synthesis image having the same color as the condition synthesized with the document image, and is a white LED.

  In the color image input device 200, the light emitted from the first light source 55 or the second light source 56 is applied to the document 57 placed on the glass document table 50, and the reflected light is converged by the spherical lens 58. Then, an image is formed on the CCD 59 of the image reading unit 53. The CCD 59 is apparently a single unit, but has three R, G, and B types of CCD elements inside. A first mirror 60, a second mirror 61, and a third mirror 62 are disposed on the path from the first light source and the second light source 56 to the CCD 59. When the original 57 is scanned by the first light source 55 or the second light source 56, the distance between the original 57 and the CCD 59 is kept constant at any position.

  In the optical drive unit 51, the power of the scanner motor 63 is transmitted to the drive pulley 65 and the wire 66 via the belt 64, and the scanner lamp unit 52 and the mirror base 65 attached to the wire 66 are driven. The scanner motor 63 is controlled by a control signal sent from a scanner control PWB (not shown).

  The first light source 55 and the second light source 56 are turned on in response to a driving voltage generated by a scanner lamp drive PWB (not shown). The operation of the scanner lamp drive PWB is controlled by a control signal sent from the scanner control PWB.

  In the color image input apparatus 200 according to the present embodiment, a document 57 is scanned by a first light source 55 and a second light source 56 which are two types of light sources having different spectral wavelength characteristics, and the first light source 55 and the second light source 56 are respectively used. Acquire the original image by. Specifically, the first light source 55 and the second light source 56 are switched between the forward pass and the return pass of the scanning operation, and the read image signals from two different light sources are acquired by one reciprocating operation of the scanner lamp unit 52. .

  In the scanning operation for the original 57, the original 57 is irradiated by the first light source 55 and the second light source 56, and the light and darkness of the reflected light is read by the three-line CCD 59 of R, G, B and converted into an analog image signal. . The R CCD extracts the red component image, the G CCD extracts the green component image, and the B CCD extracts the blue component image from the original image. This operation is called color separation.

  In the scanning operation, the scanner 57 reads the original 57 in the main scanning direction by the CCD 59 while moving the scanner lamp unit 52 in the sub scanning direction by the scanner motor 63. The image of the original 57 (the reflected light from the original 57) is optically reduced by the spherical lens 58 and projected onto the CCD 59. The reading resolution is, for example, 600 dpi.

  The R, G, B analog image signals obtained from the CCD 59 by the scanning operation are then converted into 10-bit digital signals. Each of the R, G, and B digital signals has 10-bit luminance data. The 10-bit R, G, B digital signal is then converted into an 8-bit digital signal and temporarily stored in a storage device such as a temporary storage memory or HDD.

  In the zooming operation in the enlargement / reduction scanning of the document 57, the zooming in the sub-scanning direction is performed by changing the scanning speed in the sub-scanning direction. Zooming in the main scanning direction is not performed optically but by image processing.

  The image forming apparatus 100 also includes an operation panel 40 for inputting instructions from the user. FIG. 5 is an explanatory diagram showing a basic screen of the operation panel 40. This operation panel 40 is of a touch panel type, for example, and displays various buttons on the basic screen as shown in FIG. Specifically, an embedding pattern selection button 47 and an embedding color selection button 48 are provided, and a copy button 41, an image transmission button 42, a document filing button, and other buttons are further provided.

  Here, when the embedding pattern selection button 47 is operated on the basic screen of the operation panel 40, an embedding pattern as a selectable composition image is read from the storage unit 19 and displayed on the operation panel 40. . Therefore, the user can select a synthesis image to be synthesized with the document image on the display screen of the operation panel 40. When the embedded color selection button 48 is operated, color information indicating selectable colors for the composition image is read from the storage unit 19 (lookup table) and displayed on the operation panel 40. Therefore, the user can select the color of the composition image on the display screen of the operation panel 40.

  Next, the operation of the color correction / black generation unit 15 that performs the composition process of the composition image with respect to the document image will be described. FIG. 6 is a flowchart showing the composition processing in the color correction / black generation unit 15 under the control of the control unit 600.

  When a document image is input to the color correction / black generation unit 15 in a state where a copy instruction or a print instruction for the document image is input, the control unit 600 determines whether a synthesis request is input from the user (S11). It is determined whether or not (S12). This synthesis request is a request for synthesizing a synthesis image with a document image.

  The input document image is acquired by reading the document with the color image input device 200, and passes through each part before the color correction / black generation unit 15 in the color image processing apparatus 300, so that the color correction / black generation unit. 15 is an image input into the image. Alternatively, the image is input to the color image processing apparatus 300 from an external device, and is input to the color correction / black generation unit 15 through each of the preceding stages of the color correction / black generation unit 15 in the color image processing apparatus 300.

  If it is determined in S12 that a composition request has not been input, the color correction / black generation unit 15 proceeds to S16 according to an instruction from the control unit 600 and performs the subsequent processing. On the other hand, if a composition request is input, the color correction / black generation unit 15 refers to a predetermined composition image stored in the storage unit 19 and the color of the composition image (S13), and composes the original image. A first synthesized image is created by synthesizing the work images (S14).

  The predetermined composition image to be referred to in S13 is selected on the display screen of the operation panel 40 when the user operates the embedding pattern selection button 47 of the operation panel 40. Further, the color of the image for synthesis is selected on the display screen of the operation panel 40 by the user operating the embedded color selection button 48 of the operation panel 40.

  When the embedding pattern selection button 47 is operated, an embedding pattern as a selectable composition image is read from the storage unit 19 and displayed on the operation panel 40. When the embedded color selection button 48 is operated, color information indicating selectable colors for the composition image is read from the storage unit 19 and displayed on the operation panel 40.

  The selectable color for the composition image is a color that is a condition equal color to the color of the composition image composition area of the document image. Therefore, information on selectable colors is displayed on the display screen of the operation panel 40 with reference to a color correction lookup table showing combinations of colors that are the same color as conditions.

  Thereafter, the color correction / black generation unit 15 performs various processes on the image data (S15) and outputs the image data (S16).

  The various processes in S15 differ depending on whether the combining process of S13 and S14 is performed according to the request for the combining process or when the combining process is not performed and the combining process of S13 and S14 is not performed.

  When the combining process is not performed, the color correction / black generation unit 15 uses the color correction table for converting the RGB signal into the CMYK signal for the original image according to the normal color correction / black generation process, and uses the RGB signal. Is converted into a CMYK signal and output to the spatial filter processing unit 16. Thereafter, the processed document image is processed by the output tone correction unit 17 and the tone reproduction processing unit 18 and stored in the storage unit 19 according to an instruction from the user, or on the paper in the color image output device 400. Printed.

  On the other hand, when the synthesis process is performed, the following process is performed in addition to the above process when the synthesis process is not performed. In other words, the color correction / black generation unit 15 uses a color correction table different from the color correction table for converting RGB signals into CMYK signals, and converts the RGB signals into R′G′B suitable for scan data and filing data. 'Convert to signal. Further, the R′G′B ′ signal is stored in the storage unit 19 as filing data. The R′G′B ′ signal is output as scan data directly from the color correction / black generation unit 15 or via the storage unit 19.

  Next, processing when the first combined image printed on the paper is read by the color image input apparatus 200 will be described. FIG. 7 is a flowchart showing the operation of the image forming apparatus 100 when reading the first combined image printed on the paper.

  When the user inputs a document scan instruction from the operation panel 40, the color image input apparatus 200 scans the printed first combined image. In this case, the color image input device 200 acquires a first read image that is an 8-bit RGB image by scanning with the first light source 55 (S31), and scans with the second light source 56 (S33). ), A second read image which is an 8-bit RGB image is acquired (S34).

  Note that the composition image synthesized with the document image (first synthesized image) has the same color as the condition for the composition image synthesis area of the document image under the first light source 55. Therefore, in the first read image acquired by scanning with the first light source 55, the image for synthesis is not recognized.

  The first read image and the second read image acquired by the color image input device 200 are input to the color image processing device 300, and input to the color correction / black generation unit 15 through the processing of each unit.

  Next, the color correction / black generation unit 15 determines a difference in RGB luminance values between the first read image and the second read image, and specifies a document image and a composition image included in the first combined image. (S35).

  In this process, the difference between the RGB luminance values of all the pixels of the first read image and the second read image is obtained. In this case, the difference between the RGB luminance values of the composition image portion between the first read image and the second read image becomes large, so that the composition image can be extracted. Specifically, each of the 8-bit R luminance value, G luminance value, and B luminance value is calculated for the first read image and the second read image, and when the total difference value is 255, the composition image portion It is determined that it is not. In this determination, various originals are scanned in advance by the first light source 55 and the second light source 56, and the maximum value of the difference between the RGB luminance signal values is set as a threshold value.

  Next, the color correction / black generation unit 15 synthesizes the original image specified in S35 and the synthesis image to create a second synthesized image (S36).

  In this combining process, the pixel value (color) of the second read image is adopted for the pixel determined as the combining image from the RGB luminance signal value, the combining image is combined with the original image, 2 Create a synthesized image. Therefore, the second combined image can be used to recognize the combining image under the first light source 55 and the second light source 56. Note that the pixel value (color) of the original image is used as it is for the pixels that are not determined to be a composition image.

  Next, the color correction / black generation unit 15 outputs the second combined image (S37). Specifically, the second combined image is stored in the storage unit 19 as filing data. Alternatively, it is output to the outside as scan data.

  Here, spectral characteristics of the first light source 55 and the second light source 56 of the color image input apparatus 200 are shown. FIG. 8 is a graph showing the spectral characteristics of the first light source 55 and the second light source 56 of the color image input apparatus 200.

  FIGS. 9A to 9F show first to third examples of combinations of print colors of the same condition. FIG. 9A is a graph showing the spectral characteristics in the first example of the combination of print colors of the same color, and FIG. 9B is the color under the first light source 55 and the second light source 56 for the first example. It is explanatory drawing which shows the measured value. FIG. 9C is a graph showing the spectral characteristics in the second example of the combination of print colors of the same color, and FIG. 9D is the color under the first light source 55 and the second light source 56 for the second example. It is explanatory drawing which shows the measured value. FIG. 9E is a graph showing the spectral characteristics in the third example of combinations of printing colors of the same color, and FIG. 9F is the color under the first light source 55 and the second light source 56 for the third example. It is explanatory drawing which shows the measured value.

  In addition, FIGS. 10 to 13 show examples of images in each of the above processing stages. FIG. 10A is an explanatory diagram illustrating an example of a document image, and FIG. 10B is an explanatory diagram illustrating an example of a composition image to be combined with the document image. FIG. 11 is an explanatory diagram showing an example of the first combined image created in the process of S14 of FIG. 12A is an explanatory diagram showing the first read image acquired in the process of S32 in FIG. 7, and FIG. 12B is an explanatory diagram showing the second read image acquired in the process of S34 in FIG. is there. FIG. 13A is an explanatory diagram showing a difference between the first read image and the second read image determined in the process of S35 of FIG. 7, and FIG. 13B is a diagram created in the process of S36 of FIG. It is explanatory drawing which shows 2 synthesized images.

  In the color image input device 200, an optical filter that cuts a specific wavelength is interposed between the first light source 55 or the second light source 56 and the glass platen 50, so that the first light source 55 or the second light source 55 can be used. The spectral characteristics of the light source 56 can be adjusted. This configuration makes it possible to control the visualization of the composition image.

  Finally, each block of the color image processing apparatus 300, particularly the color correction / black generation unit 15, may be configured by hardware logic, or may be realized by software using a CPU as follows.

  That is, the color image processing apparatus 300 includes a CPU (central processing unit) that executes instructions of a control program that realizes each function, a ROM (read only memory) that stores the program, and a RAM (random access memory) that expands the program. ), A storage device (recording medium) such as a memory for storing the program and various data. An object of the present invention is a recording medium in which the program code (execution format program, intermediate code program, source program) of the control program of the color image processing apparatus 300, which is software that implements the functions described above, is recorded so as to be readable by a computer Can also be achieved by reading the program code recorded in the recording medium and executing it by the computer (or CPU or MPU).

  Examples of the recording medium include a tape system such as a magnetic tape and a cassette tape, a magnetic disk such as a floppy (registered trademark) disk / hard disk, and an optical disk such as a CD-ROM / MO / MD / DVD / CD-R. Card system such as IC card, IC card (including memory card) / optical card, or semiconductor memory system such as mask ROM / EPROM / EEPROM / flash ROM.

  The color image processing apparatus 300 may be configured to be connectable to a communication network, and the program code may be supplied via the communication network. The communication network is not particularly limited. For example, the Internet, intranet, extranet, LAN, ISDN, VAN, CATV communication network, virtual private network, telephone line network, mobile communication network, satellite communication. A net or the like is available. Further, the transmission medium constituting the communication network is not particularly limited. For example, even in the case of wired such as IEEE 1394, USB, power line carrier, cable TV line, telephone line, ADSL line, etc., infrared rays such as IrDA and remote control, Bluetooth ( (Registered trademark), 802.11 wireless, HDR, mobile phone network, satellite line, terrestrial digital network, and the like can also be used. The present invention can also be realized in the form of a computer data signal embedded in a carrier wave in which the program code is embodied by electronic transmission.

  The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in the embodiments are also included. It is included in the technical scope of the present invention.

15 color correction / black generation unit (first synthesis processing unit, second synthesis processing unit, discrimination unit)
DESCRIPTION OF SYMBOLS 19 Memory | storage part 40 Operation panel 47 Embedding pattern selection button 48 Embedment color selection button 52 Scanner lamp unit 53 Image reading part 55 1st light source 56 2nd light source 57 Original document 59 CCD
DESCRIPTION OF SYMBOLS 100 Image forming apparatus 200 Color image input apparatus 300 Color image processing apparatus 400 Color image output apparatus 600 Control part

Claims (5)

An image processing apparatus including a first composition processing unit that composes a composition image in a composition image composition region of a document image to create a first composited image , wherein the first composition processing unit includes the first composition processing unit. On the colorimetry of the first print image obtained by printing one synthesized image, the pixel value of each pixel of the synthesis image is the pixel of the corresponding pixel in the synthesis image synthesis area under the first light source. The pixel value of each pixel of the image for synthesis is the pixel value of the corresponding pixel in the image synthesis area for synthesis under a second light source that has the same color as the condition and has a spectral characteristic different from that of the first light source. An image processing device configured to set the different pixel values and combining the combining image with the combining image combining region of the document image to create the first combined image ;
An original reading device for reading an original image,
The original reading apparatus includes the first light source and the second light source, reads the original image with the first light source and the second light source, and uses the first read image with the first light source and the second light source. A second scanned image,
The image processing apparatus includes a determination unit that compares the first read image and the second read image with respect to the first print image to determine the presence or absence of the image for synthesis in the first print image. ,
The image processing apparatus includes a second synthesis processing unit,
The determination unit extracts the composition image and the document image when determining that the composition image is present in the first print image,
The second synthesis processing unit adopts the pixel value of the second read image for the pixel of the synthesis image when the discrimination unit determines that the synthesis image is present in the first print image. For the other pixels, the original image pixel extracted by the determination unit is adopted, and the original image and the composition image are combined to create a second combined image. An image forming apparatus. A printing device for printing images on paper;
The image forming apparatus according to claim 1, wherein the printing apparatus prints the first combined image with a combination of toners including a color material having an absorption component and a reflection component in a visible light region. An image processing step comprising a first compositing processing step of compositing a compositing image in a compositing image compositing region of a document image to create a first composited image , wherein the first compositing processing step includes the first compositing processing step. On the colorimetry of the first print image obtained by printing one synthesized image, the pixel value of each pixel of the synthesis image is the pixel of the corresponding pixel in the synthesis image synthesis area under the first light source. The pixel value of each pixel of the image for synthesis is the pixel value of the corresponding pixel in the image synthesis area for synthesis under a second light source that has the same color as the condition and has a spectral characteristic different from that of the first light source. An image processing step for setting the different pixel values and combining the combining image with the combining image combining region of the document image to create the first combined image ;
A document reading step of reading a document image with the first light source and the second light source, and obtaining a first read image with the first light source and a second read image with the second light source;
The image processing step includes a determination step of comparing the first read image and the second read image with respect to the first print image to determine the presence or absence of the composition image in the first print image. ,
The image processing step includes a second synthesis processing step,
In the determination step, when it is determined that the composition image is present in the first print image, the composition image and the document image are extracted,
The second composition processing step adopts the pixel value of the second read image for the pixel of the composition image when it is determined in the determination step that the composition image is present in the first print image. For the other pixels, the original image pixels extracted in the determination step are adopted, and the original image and the composition image are combined to create a second combined image. An image forming method. A program for causing a computer to function as each unit of the image forming apparatus according to claim 1. The computer-readable recording medium which recorded the program of Claim 4 .